repetitio est mater studiorum – repetition is the mother of learning

Superficial, big, important

Chapter 7, Bones, Part 1:

The Axial Skeleton Skull Spine Sternum Ribs Auditory ossicles Hyoid Bone

Goal: Learn and locate the bones and

markings of the axial skeleton

thorax

Developed by

John Gallagher, MS, DVM

Bones of the Skull

Bones of the Skull, cont’d

Cranial Bones, AKA

calvarium

vs.

Facial Bones

Bones of the Skull, cont’d

Bones of the Calvarium

Frontal (forehead)

– Anterior fossa of base of skull

– Frontal Crests

More prominent in male

– Frontal sinuses

Parietal (2)

– Sutures

Occipital – Foramen Magnum

– Occipital Condyles articulate with

C1

– Occipital Crest

Bones of the Calvarium, cont’d

Temporal (4 parts): – Squamous (very thin),

– Mastoid (means breast-like) process Small sinus

– Petrous Houses inner ear

Acoustic meatus

Jugular foramen

– Zygomatic process

– Styloid Process

―In one of these, the squamosal section of the temporal bone had been

crushed, and another showed a jagged hole through the parietal bone.‖

The Bounty Trilogy, 1788

Bones of the Calvarium floor

Sphenoid – Sella turcica houses pituitary

gland

Ethmoid (sieve)

– Cribriform plate for olfactory nerve

– Crista galli

– Part of nasal septum

Frontal

Temporal – Petrous part

Occipital – Foramen magnum

Facial bones

Maxilla (2)

– Alveolar margin for teeth

– Maxillary sinus

– Anterior portion of hard palate

Palatine (2)

– Posterior aspect of hard palate

Nasal (2)

Inferior Nasal conchae (2)

– Will be covered in Respiratory

System

Facial bones, cont’d

Zygomatic (2) AKA cheek bones

– Zygomatic process of temporal bone

Lacrimal (2) – Lacrimal sac

Vomer – Part of nasal septum

Facial bones, cont’d

Mandible – Mandibular condyles

(TMJ)

– Mandibular notch

– Coronoid process

– Ramus

– Angle

– Mental foramen

Sutures and Fontanels

Fibrous Articulation, no

movement, fused in

adulthood

– Lambdoidal—betw occipital

and parietal

– (mid) Saggital --- betw parietals

– Coronal– betw frontal and

parietals

– Squamous – betw parietals and

temporals

Anterior and Posterior

Fontanels

– ―Soft spot‖ of Newborn

Paranasal Sinuses

Frontal

Ethmoid

Sphenoid

Maxillary

Narrow passageways from each

sinus provide communication with

nasal cavity

Sinusitis

-itis = inflammation

Bacterial, viral, fungal,

allergic

Swelling causes poor

drainage and pressure

differentials

– Sinus headache

Treatment might include

decongestants, e.g.,

pseudephedrine

Hyoid Bone

Inferior to the

mandible

Superior to the larynx

Supports many

cervical muscles

Supports the larynx

The Vertebral Column

7 Cervical

12 Thoracic

5 Lumbar

5 Sacral (fused)

4 Coccygeal (usually)

Curvatures:

Cervical, Thoracic,

Lumbar, Sacral

A ―Typical‖ Vertebra

Body and intervertebral disks

Spinous Process

Intervertebral Foramina

Articular processes/facets

Superior

Inferior

Vertebral (neural) Arch

Pedicles and Laminae

Vertebral Canal/foramen

Cervical Vertebrae (C1 – C 7)

C1 = Atlas (no body)

C1-C2 – site of rotation

C2 = Axis (dens)

C3 - C6 are similar

Note the transverse foramina in each cervical vertebra – Vertebral Artery/Vein

C7 has the vertebra prominens

C1

Thoracic Vertebrae (T1 - T12)

Large Spinous Processes

Articulations for ribs, both superior and inferior

Lumbar Vertebrae (L1 - L5)

Body

Spinous Process

Lamina

Articular Facets

Transverse Process

Pedicle

Intervertebral Articulation

Intervertebral Disk

Nucleus Pulposus

Annulus Fibrosus – Fibrocartilage

See Fig. 8-9

Disc Problems

Most common sites for disc problems: – C5 - C6

– L4 - L5

– L5 - S1

Laminectomy ( surgical removal vertebral

arch by shaving laminae to access disc)

Fig 7.14

Damage to the Intervertebral Discs

Annulus

fibrosus

Sacrum (5 fused)

Coccyx (3-5 fused)

Sacroiliac joint

Sacral Foramina

Thoracic (Rib) Cage

Protection and muscle attachments

Ribs – 12 pairs – 1 - 7 are ―true‖ ribs, with attachment to the sternum

– 8 - 12 attach indirectly to the sternum, or not at all

Costal Cartilages

Thoracic (Rib) Cage, cont’d

Sternum – Manubrium

Clavicular Notch

– Body

– Xiphoid

Cliffs of Moher, Co Clare, Ireland